$1$

The main difference between Go$-$Back $N($GBN$)$ and Selective Repeat protocols:

A$.$ GBN resend whole packets in the window if one packet is lost, while Selective Repeat don't.

B$.$ None is true.

C$.$ GBN is pipelined protocol, while Selective Repeat is stop and wait protocol.

D$.GBN$ is not reliable as Selective Repeat.

E$.$ Selective Repeat is pipelined protocol, while GBN is stop and wait protocol.

$2$

Select the wrong statement:

In Dijkstra algorithm:

A$.$ Based on greedy method.

B$.$ Number of edges controls the time complexity.

C$.$ Best case scenario for time complexity is $O(n^2)$

D$.$ Used for link state routing algorithms.

E$.$ Solution starts from the source vertex always.

$3$

Queuing delay is:

A$.$ None is true.

B$.$ Related to propagation time.

C$.$ Related to transmission time.

D$.$ Related to the channel capacity.

E$.$ Related to nodal processing.